//使用标准 I/O
#include<stdio.h>
#include<stdlib.h>  //提供 exit()的原型
int main(int argc, char *argv[])
{
    int ch;
    FILE *fp;  //"文件指针"
    unsigned long count = 0;
    if(argc!=2)
    {
        printf("Usage: %s filemane\n", argv[0]);
        exit(EXIT_FAILURE);
    }
    if((fp=fopen(argv[1], "r")) == NULL)
    {
        printf("Can't open %s\n", argv[1]);
        exit(EXIT_FAILURE);
    }
    while((ch=getc(fp)) != EOF)
    {
        putc(ch, stdout);  //与putchar(ch);相同
        count++;
    }
    fclose(fp);
    printf("\nFile %s has %lu characters\n", argv[1], count);

    return 0;
}